Patent GB-610802-A (GB)
Title: Production of artificial fibres
IPC: D01D5/06
Filed: 1948-02-27
Abstract: Discontinuous fibres are obtained by dispersing a flowable composition containing a thermoplastic material and a thermosetting resin in the thermoplastic state into a fluid which is a non-solvent for the thermoplastic material and the resin so as to form discontinuous fibres, and the fibres are cured in presence of a catalyst.  The curing or hardening <PICT:0610802/IV(a)/1> <PICT:0610802/IV(a)/2> may be effected during the production of the fibres or at a later stage, e.g. after they have been formed into yarns, fabrics, felts or other structures.  The fibres may be mixed with other fibres and in such mixtures some of the fibres may be potentially adhesive so that upon activation the adhesive fibres will bind the other fibres together.  The fibres containing the thermosetting resin prior to curing may serve as the potentially adhesive fibres.  The thermosetting resin may be a urea, melamine, phenol, or sulphonamide-aldehyde resin, or an alkyd resin.  The thermoplastic ingredient may be a shellac, copal, dammar, mastic, cumarone, indene, styrene, polyvinyl, or sulphur-olefine resin, or a polyamide, rubber derivative, synthetic rubber, cellulose ester, or cellulose ether.  The composition may be rendered flowable by dissolving in organic solvents or by melting.  The composition may be dispersed into a liquid or gas with sufficient pressure to form a large number of fibres.  An atomizer or spray gun may be used, or the fibres may be formed by electrical dispersion in a gaseous medium. The fibres may be collected by deposition on a belt or drum and they may be in a tacky or non-tacky condition at the point of deposit.  If tacky they will adhere to each other so as to form a reticulated structure.  As shown in Fig. 2, the thermosetting resin composition is forced by means of spray gun 1 into a heated gas contained in chamber 20 so as to obtain discontinuous resin fibres and at the same time non-adhesive felt or paper-making fibres 21 are blown into the chamber 20 through conduit 22, and the mixture of fibres is collected on the belt 24.  The bat of mixed fibres is compressed by rolls 25, 26.  The rolls may be heated to render the resin fibres tacky, or the bat of fibres may be treated with an organic solvent.  The bat of fibres may be passed into a heated chamber for the purpose of curing the thermosetting resin.  As shown in Fig. 3, the solution is dispersed inside chamber 30 by means of several spray guns 1 and the fibres so formed are deposited on a wire-screen drum 31, suction being applied to the interior of the drum.  The deposit of fibres on the drum is removed by a stripping roll 35 and the bat of fibres 27 is passed through a curing chamber 36.  As non-adhesive fibres for mixing with the p  thermosetting resin fibres, there may be used fibres of cotton, flax, jute, kapok, wool, silk, hair, wood, regenerated cellulose, cellulose esters and ethers, rubber, alginates, gelatine, casein, glass, asbestos, mineral wool, natural and synthetic resins.  The non-adhesive fibres, if artificial, may be obtained by a similar method to that for the thermosetting resin fibres.  Thus, in the apparatus of Fig. 2, the non-adhesive fibres may be produced by use of a second spray gun placed in the chamber 20 instead of the conduit 22.  The potentially adhesive thermosetting resin fibres may be formed and dispersed in an aqueous suspension of paper-making fibres as in the head box of a Fourdrinier or cylinder paper machine, from which box the suspension of fibres is delivered to the wire-cloth of the paper machine.  In an example, a solution comprising polyvinyl butyral, urea-formaldehyde butanol ether resin, plasticizer, and titanium dioxide, with butyl alcohol as solvent is sprayed so as to form fibres.  Polyamide fibres are also dispersed in the spray chamber.  The fibre mixture so obtained is carded, spun, and woven.  The fabric is heated to activate the urea-aldehyde fibres and the fabric is then cured at 260 DEG  F. until the fibres are no longer thermoplastic.  The resulting fabric has high wet strength and wear resistance. Catalysts specified are salts of chloracetic acid, ammonium thiocyanate, and p-toluene sulphamic acid.ALSO:Discontinuous fibres are obtained by dispersing a flowable composition containing a thermoplastic material and a thermosetting resin in the thermoplastic state into a fluid which is a non-solvent for the thermoplastic material and the resin so as to form discontinuous fibres, and the fibres are cured in presence of a catalyst.  The curing or hardening may be effected during the production of the fibres or at a later stage, e.g. after they have been formed into yarns, fabrics, felts or other structures.  The fibres may be mixed with other fibres and in such mixtures some of the fibres may be potentially adhesive so that upon activation the adhesive fibres will bind the other fibres together.  The fibres containing the thermosetting resin prior to curing may serve as the potentially adhesive fibres.  The thermosetting resin may be a urea, melamine, phenol, or sulphonamide-aldehyde resin, or an alkyd resin.  The thermoplastic ingredient may be a shellac, copal, dammar, mastic, cumarone, indene, styrene, polyvinyl, or sulphur-olefine resin, or a polyamide, rubber, rubber derivative, synthetic rubber, cellulose ester, or cellulose ether.  The composition may be rendered flowable by dissolving in organic solvents or by melting.  The composition may be dispersed into a liquid or gas with sufficient pressure to form a large number of fibres.  An atomizer or spray gun may be used, or the fibres may be formed by electrical dispersion in a gaseous medium.  The fibres may be collected by deposition on a belt or drum and they may be in a tacky or non-tacky condition at the point of deposit.  If tacky they will adhere to each other so as to form a reticulated structure.  As non-adhesive fibres for mixing with the thermosetting resin fibres, there may be used fibres of cotton, flax, jute, kapok, wool, silk, hair, wood, regenerated cellulose, cellulose esters and ethers, rubber, alginates, gelatine, casein, glass, asbestos, mineral wool, natural and synthetic resins.  The non-adhesive fibres, if artificial, may be obtained by a similar method to that for the thermosetting resin fibres.  In an example, a solution comprising polyvinyl butyral, urea-formaldehyde butanol ether resin, plasticizer, and titanium dioxide, with butyl alcohol as solvent is sprayed so as to form fibres.  Polyamide fibres are also dispersed in the spray chamber.  The fibre mixture so obtained is carded, spun and woven.  The fabric is heated to p  activate the urea-aldehyde fibres and the fabric is then cured at 260 DEG  F. until the fibres are no longer thermoplastic.  The resulting fabric has high wet strength and wear resistance. Catalysts specified are salts of chloracetic acid, ammonium thiocyanate and p-toluene sulphamic acid.